JP3737306B2 - Optical product and manufacturing method thereof - Google Patents

Description

【００２６】
本発明の目的には、ポリマーのブレンドが、９０°光散乱で、７×１０^-3ｃｍ^-1未満のレイリー比（Ｒ₉₀°）で特徴づけられれば、前記ポリマーは相溶性であると考えられる。レイリー比、Ｒθ、は従来知られている特性であり、Ｍ．Ｋｅｒｋｅｒ，Ｔｈｅ Ｓｃａｔｔｅｒｉｎｇ ｏｆ Ｌｉｇｈｔ ａｎｄ Ｏｔｈｅｒ Ｅｌｅｃｔｒｏｍａｇｎｅｔｉｃ Ｒａｄｉａｔｉｏｎ，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ，Ｓａｎ Ｄｉｅｇｏ，１９６９で議論されているように、媒体が単位強度の非偏光に照らされたとき、単位体積により方向θにステラジアンあたり散乱されるエネルギーである。測定に用いられる光源は一般的に可視領域の波長を有するレーザーである。通常は、ホログラム書き込みに用いられる波長を使用する。散乱測定は、投光露光された光記録材料上で行われる。散乱された光は、入射光より９０°の角度で、典型的には光検出器により集められる。レーザー波長を中心とした狭帯域フィルタを光検出器の前に置き蛍光を遮断することも可能であるが、そのような手段が必要というわけではない。レイリー比は、典型的にはレイリー比が既知の参照物質のエネルギー散乱との比較で得られる。
【００２７】
例えば単一のガラス転移温度を示すなどの従来の試験法により混和性であると考えられるポリマーブレンドは、相溶性でもあるのが典型的であり、すなわち混和性は相溶性の一部である。したがって、標準的な混和性ガイドラインおよび表が、相溶性のあるブレンドを選択するのに有用である。しかし、混和性でないポリマーブレンドが上述の光散乱試験により相溶性であることもある。
【００２８】
ポリマーブレンドは、従来法により測定して単一のガラス転移温度、Ｔ_g、を示すと、一般的に混和性であると考えられる。非混和性のブレンドは、それぞれのポリマーのＴ_g値に対応する２つのガラス転移温度を示すのが典型的である。Ｔ_g試験は、熱流量の段階的変化（通常縦軸）としてＴ_gを示す示差走査熱量測定法（ＤＳＣ）により実施されるのが普通である。報告されるＴ_gは、縦軸が転移の前後の外挿されたベースラインの中点値に達する温度である。Ｔ_gを測定するのに動的機械分析（ＤＭＡ）を用いるのも可能である。ＤＭＡでは、ガラス転移領域で数桁低下する、材料の貯蔵弾性率を測定できる。ブレンド中の各ポリマーが、それぞれ互いに近いＴ_gを持つ場合もある。そのような場合には、Ｂｒｉｎｋｅ ｅｔ ａｌ．，“Ｔｈｅ ｔｈｅｒｍａｌ ｃｈａｒａｃｔｅｒｉｚａｔｉｏｎ ｏｆ ｍｕｌｔｉ−ｃｏｍｐｏｎｅｎｔ ｓｙｓｔｅｍｓ ｂｙ ｅｎｔｈａｌｐｙ ｒｅｌａｘａｔｉｏｎ，" Ｔｈｅｒｍｏｃｈｉｍｉｃａ Ａｃｔａ．，２３８（１９９４）， ａｔ ７５で議論されているような、従来の方法を用いて重なったＴ_gを分離するべきである。
【００２９】
混和性を示すマトリックスポリマーと光活性モノマーは、いくつかの方法で選択できる。例えば、Ｏ．Ｏｌａｂｉｓｉ ｅｔ ａｌ．，Ｐｏｌｙｍｅｒ−Ｐｏｌｙｍｅｒ Ｍｉｓｃｉｂｉｌｉｔｙ，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ，ＮｅｗＹｏｒｋ，１９７９；Ｌ．Ｍ．Ｒｏｂｅｓｏｎ，ＭＭＩ．Ｐｒｅｓｓ Ｓｙｍｐ．Ｓｅｒ．，２，１７７，１９８２；Ｌ．Ａ．Ｕｔｒａｃｋｉ，Ｐｏｌｙｍｅｒ Ａｌｌｏｙｓ ａｎｄ Ｂｌｅｎｄｓ：Ｔｈｅｒｍｏｄｙｎａｍｉｃｓ ａ ｎｄ Ｒｈｅｏｌｏｇｙ，Ｈａｎｓｅｒ Ｐｕｂｌｉｓｈｅｒｓ，Ｍｕｎｉｃｈ，１９８９；Ｓ．Ｋｒａｕｓｅ ｉｎ Ｐｏｌｙｍｅｒ Ｈａｎｄｂｏｏｋ，Ｊ．Ｂｒａｎｄｒｕｐ ａｎｄ Ｅ．Ｈ．Ｉｍｍｅｒｇｕｔ，Ｅｄｓ．，３ｒｄ Ｅｄ．，Ｗｉｌｅｙ Ｉｎｔｅｒｓｃｉｅｎｃｅ，Ｎｅｗ Ｙｏｒｋ，１９８９，ｐｐ．ＶＩ３４７−３７０などのような、混和性のポリマーに関する出版された編集物が何冊か利用できるが、上記の資料の開示は本願で参考のため取り入れられている。所望のポリマーがこのような参考資料に見つからなくても、特定の手法を用いれば、対照試料を使用して相溶性のある光記録材料を決定できる。
【００３０】
混和性または相溶性のあるブレンドの決定は、一般的に混和性を促進する分子間相互作用を考慮すれば、さらに支援される。例えば、ポリスチレンおよびポリ（メチルビニルエーテル）は、メチルエーテル基とフェニル環の間に働く互いに引きつけ合う相互作用により、混和性があることはよく知られている。したがって、あるポリマー中ではメチルエーテル基を他のポリマー中ではフェニル基を用いることにより、二つのポリマーの混和性を、または少なくとも相溶性を高めることが可能である。イオン性相互作用を提供する適当な官能基を取り入れることにより、混和性でないポリマーを混和性にできることが示されている（Ｚ．Ｌ．Ｚｈｏｕ ａｎｄ Ａ．Ｅｉｓｅｎｂｅｒｇ，Ｊ．Ｐｏｌｙｍ．Ｓｃｉ．，Ｐｏｌｙｍ．Ｐｈｙｓ．Ｅｄ．，２１（４），５９５，１９８３；Ｒ．Ｍｕｒａｌｉａｎｄ Ａ．Ｅｉｓｅｎｂｅｒｇ，Ｊ．Ｐｏｌｙｍ．Ｓｃｉ．，Ｐａｒｔ Ｂ：Ｐｏｌｙｍ．Ｐｈｙｓ．，２６（７），１３８５，１９８８；ａｎｄ Ａ Ｎａｔａｎｓｏｈｎ ｅｔ ａｌ．，Ｍａｋｒｏｍｏｌ．Ｃｈｅｍ．，Ｍａｃｒｏｍｏｌ．Ｓｙｍｐ．，１６，１７５，１９８８参照のこと）。例えば、ポリイソプレンとポリスチレンは非混和性である。しかし、ポリイソプレンが部分的に（５％）スルホン化され、４−ビニルピリジンがポリスチレンと共重合されると、これらの官能性ポリマーのブレンドは混和性となる。スルホン化された基とピリジン基（プロトン移動）の間のイオン性相互作用が、このブレンドを混和性にする推進力であると考えられている。同様に、通常は非混和性であるポリスチレンとポリ（アクリル酸エチル）は、ポリスチレンを少しスルホン化すれば、混和性になる（Ｒ．Ｅ． Ｔａｙｌｏｒ−Ｓｍｉｔｈ ａｎｄ Ｒ．Ａ． Ｒｅｇｉｓｔｅｒ，Ｍａｃｒｏｍｏｌｅｃｕｌｅｓ，２６，２８０２，１９９３参照）。電荷移動も、非混和性のポリマーを混和性にするため利用されてきた。例えば、ポリ（アクリル酸メチル）とポリ（メタクリル酸メチル）は非混和性であるが、ポリ（アクリル酸メチル）を（Ｎ−エチルカルバゾール−３−イル）メチルアクリレート（電子供与体）と共重合し、ポリ（メタクリル酸メチル）を２−［（３，５−ジニトロベンゾイル）オキシ］エチルメタクリレート（電子受容体）と共重合すると、供与体と受容体を適量用いれば、それらのポリマーのブレンドは混和性になる（Ｍ．Ｃ．Ｐｉｔｏｎ ａｎｄ Ａ．Ｎａｔａｎｓｏｈｎ，Ｍｃｒｏｍｏｌｅｃｕｌｅｓ，２８，１５，１９９５参照）。ポリ（メタクリル酸メチル）とポリスチレンも、対応する供与体−受容体コモノマーを用いれば混和性にできる（Ｍ．Ｃ．Ｐｉｔｏｎ ａｎｄ Ａ．Ｎａｔａｎｓｏｈｎ，Ｍａｃｒｏｍｏｌｅｃｕｌｅｓ，２８，１６０５，１９９５参照）。
【００３１】
Ａ．Ｈａｌｅ ａｎｄ Ｈ．Ｂａｉｒ，Ｃｈ．４−“Ｐｏｌｙｍｅｒ Ｂｌｅｎｄｓ ａｎｄ Ｂｌｏｃｋ Ｃｏｐｏｌｙｍｅｒｓ，"Ｔｈｅｒｍａｌ Ｃｈａｒａｃｔｅｒｉｚａｔｉｏｎ ｏｆ Ｐｏｌｙｍｅｒｉｃ Ｍａｔｅｒｉａｌｓ，２ｎｄ Ｅｄ．，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ，１９９７の中で発表された最近の概略で考慮されているように、ポリマーの混和性または相溶性の試験方法にはさまざまな種類がある。例えば、光学的方法の領域では、不透明は２層から成る物質を示すのが典型的であり、透明は混和性の系を表すのが一般的である。混和性を評価する他の方法としては、中性子散乱、赤外分光法（ＩＲ）、核磁気共鳴法（ＮＭＲ）、ｘ線散乱および回折、蛍光、ブリユアン散乱、溶融滴定、熱量法および化学発光がある。例えば、Ｌ．Ｒｏｂｅｓｏｎ，ｓｕｐｒａ，；Ｓ．Ｋｒａｕｓｅ，Ｃｈｅｍｔｒａｃｔｓ−Ｍａｃｒｏｍｏｌ．Ｃｈｅｍ．，２，３６７，１９９１ａ；Ｄ．Ｖｅｓｅｌｙ ｉｎ Ｐｏｌｙｍｅｒ Ｂｌｅｎｄｓ ａｎｄ Ａｌｌｏｙｓ，Ｍ．Ｊ．Ｆｏｌｋｅｓ ａｎｄ Ｐ．Ｓ．Ｈｏｐｅ，Ｅｄｓ．，Ｂｌａｃｋｉｅ Ａｃａｄｅｍｉｃ ａｎｄ Ｐｒｏｆｅｓｓｉｏｎａｌ，Ｇｌａｓｇｏｗ，ｐｐ．１０３−１２５；Ｍ．Ｍ．Ｃｏｌｅｍａｎ ｅｔ ａｌ．，Ｓｐｅｃｉｆｉｃ Ｉｎｔｅｒａｃｔｉｏｎｓ ａｎｄ ｔｈｅ Ｍｉｓｃｉｂｉｌｉｔｙ ｏｆ Ｐｏｌｙｍｅｒ Ｂｌｅｎｄｓ， Ｔｅｃｈｎｏｍｉｃ Ｐｕｂｌｉｓｈｉｎｇ，Ｌａｎｃａｓｔｅｒ，ＰＡ，１９９１；Ａ．Ｇａｒｔｏｎ，Ｉｎｆｒａｒｅｄ Ｓｐｅｃｔｒｏｓｃｏｐｙｏｆ Ｐｏｌｙｍｅｒ Ｂｌｅｎｄｓ，Ｃｏｍｐｏｓｉｔｅｓ ａｎｄ Ｓｕｒｆａｃｅｓ，Ｈａｎｓｅｒ，Ｎｅｗ Ｙｏｒｋ，１９９２；Ｌ．Ｗ．Ｋｅｌｔｓ ｅｔ ａｌ．，Ｍａｃｒｍｏｌｅｃｕｌｅｓ，２６，２９４１，１９９３；Ｊ．Ｌ．Ｗｈｉｔｅ ａｎｄ Ｐ．Ａ．Ｍｉｒａｕ，Ｍａｃｒｍｏｌｅｃｕｌｅｓ，２６，３０４９，１９９３；Ｊ．Ｌ．Ｗｈｉｔｅ ａｎｄ Ｐ．Ａ．Ｍｉｒａｕ，Ｍａｃｒｍｏｌｅｃｕｌｅｓ，２７，１６４８，１９９４；Ｃ．Ａ．Ｃｒｕｚ ｅｔ ａｌ．，Ｍａｃｒｍｏｌｅｃｕｌｅｓ，１２，７２６，１９７９；Ｃ．Ｊ．Ｌａｎｄｒｙ ｅｔ ａｌ．，Ｍａｃｒｍｏｌｅｃｕｌｅｓ，２６，３５，１９９３を参照のこと。
【００３２】
ポリマーマトリックスの中へ反応性の基を取り入れることにより、そのような基がホログラフィ記録工程の間光活性モノマーと反応できる場合は、非相溶性であるポリマーの相溶性が高められてきた。光活性モノマーの一部はそのようにして記録の間マトリックスにグラフトされる。これらのグラフトが十分あれば、記録の間相分離を防止または低減することが可能である。しかし、グラフトされた部分とモノマーの屈折率が比較的似ている時は、あまり多くのグラフトがあると、例えば３０％を超えるモノマーがマトリックスにグラフトされていると、望ましくなく屈折率コントラストを低下させるであろう。
【００３３】
本発明のホログラフィ記録媒体は、ホログラフィ書き込みと読み出しが可能なように、光記録材料を適当に支持することにより形成される。典型的には、媒体の製造は、マトリックス前駆体／光画像化システム混合物を、例えば混合物を封じ込めるためのガスケットを用いて、２枚のプレートの間に付着させるものである。プレートは、ガラスが一般的であるが、データ書き込みに用いる放射に対して透明な物質、例えばポリカーボネートまたはポリ（メタクリル酸メチル）などのプラスティックを使用することも可能である。プレートの間にスペーサーを入れて記録媒体の所望の厚さを保つことも可能である。マトリックス硬化の間、材料が収縮してプレートに応力がかかる可能性があるが、このような応力はプレートの平行度および／または間隔を変え、媒体の光学的特性を損ねる。そのような影響を減らすため、平行度および／または間隔の変化に対応して調節できるマウント、例えば真空チャックを備えた装置にプレートを据えることが有用である。このような装置では、従来の干渉計測法により平行度をリアルタイムで観察し、硬化の間必要な調整をすることができる。このような装置は、例えば米国特許出願第０８／８６７５６３号（我々の参照番号Ｃａｍｐｂｅｌｌ−Ｈａｒｒｉｓ−Ｌｅｖｉｎｏｓ ３−５−３）で議論されており、その開示は参考のため本願に取り入れられている。本発明の光記録材料はそのほかの方法でも支持することができる。例えば、マトリックス硬化の前にマトリックス前駆体／光画像化システム混合物を、例えばＶｙｃｏｒなどの微細孔ガラス材料のような基材の細孔に付着させることが考えられる。密閉型成形や板押出などの従来のポリマー加工も考えられる。層になった媒体、すなわち光記録材料が間に付着されている、例えばガラスなどの複数の基板を有する媒体も考えられる。
【００３４】
本発明の媒体は上述のようなホログラフィシステムで使用できる。ホログラフィ媒体に記憶できる情報の量は、光記録材料の屈折率コントラストΔｎおよび光記録材料の厚さ、ｄの積に比例する（屈折率コントラスト、Δｎは従来知られており、平面波の体積ホログラムが書き込まれる材料の屈折率の正弦変動の大きさとして定義される。屈折率は、ｎ（ｘ）＝ｎ₀＋Δｎｃｏｓ（Ｋ_x）のように変わり、ここでｎ（ｘ）は空間的に変動する屈折率、ｘは位置ベクトル、Ｋ_xは格子波数ベクトルおよびｎ₀は媒体のベースライン屈折率である。例えば、Ｐ．Ｈａｒｉｈａｒａｎ，Ｏｐｔｉｃａｌ Ｈｏｌｏｇｒａｐｈｙ：Ｐｒｉｎｃｉｐｌｅｓ， Ｔｅｃｈｎｉｑｕｅｓ， ａｎｄ Ａｐｐｌｉｃａｔｉｏｎｓ， Ｃａｍｂｒｉｄｇｅ Ｕｎｖｅｒｓｉｔｙ Ｐｒｅｓｓ，Ｃａｍｂｒｉｄｇｅ，１９９１，ａｔ４４を参照）。材料のΔｎは、媒体に記録される単一の体積ホログラムまたは多重組の体積ホログラムの回折効率から計算されるのが典型的である。前記Δｎは書き込み前の媒体に関連があるが、記録の後行われる測定によって観察される。本発明の光記録材料は３×１０^-3以上のΔｎを示すのが好都合である。
【００３５】
他の光学製品の例としては、ビームフィルタ、ビーム配向体、偏向板および光カプラーがある（例えば、Ｌ．Ｓｏｌｙｍａｒ ａｎｄ Ｄ．Ｃｏｏｋｅ，Ｖｏｌｕｍｅ Ｈｏｌｏｇｒａｐｈｙ ａｎｄ Ｖｏｌｕｍｅ Ｇｒａｔｉｎｇｓ，Ａｃａｄｅｍｉｃ Ｐｒｅｓｓ，３１５−３２７（１９８１）を参照のこと。同資料の開示を参考のため本願に取り入れている）。ビームフィルタは、ある特定の角度で飛行してくる入射レーザー光の一部を、その他の光から分離する。具体的には、厚い透過ホログラムのブラッグ選択性は、特定の角度で入射してくる光を選択的に回折させ、他の角度からくる光は偏向されずにホログラムを通過する（Ｊ．Ｅ．Ｌｕｄｍａｎ ｅｔ ａｌ．，“Ｖｅｒｙ ｔｈｉｃｋ ｈｏｌｏｇｒａｐｈｉｃ ｎｏｎｓｐａｔｉａｌ ｆｉｌｔｅｒｉｎｇ ｏｆ ｌａｓｅｒｂｅａｍｓ，"Ｏｐｔｉｃａｌ Ｅｎｇｉｎｅｅｒｉｎｇ，Ｖｏｌ．３６，Ｎｏ．６，１７００（１９９７）を参照のこと。同資料の開示を参考のため本願に取り入れている）。ビーム配向体は、ブラッグ角で入射してくる光を偏向するホログラムである。光カプラーは、典型的には光を光源からターゲットへ向けさせるビーム偏光板の組合わさったものである。一般的にホログラフィ光学素子と言われるこれらの製品は、データ記憶に関して以上で述べたように、記録媒体内に、特定の光学干渉パターンを作ることにより製造される。これらのホログラフィ光学素子用の媒体は、記録媒体や導波管に関して本願で述べた技術により製造できる。
【００３６】
上述のとおり、本願で述べた材料の原則はホログラム形成のみならず、導波管のような光学的伝送素子の形成にも適用される。ポリマー状の光導波路は、例えばＢ．Ｌ．Ｂｏｏｔｈ，“Ｏｐｔｉｃａｌ Ｉｎｔｅｒｃｏｎｎｅｃｔｉｏｎ Ｐｏｌｙｍｅｒｓ，"ｉｎ Ｐｏｌｙｍｅｒｓ ｆｏｒ Ｌｉｇｈｔｗａｖｅ ａｎｄ Ｉｎｔｅｇｒａｔｅｄ Ｏｐｔｉｃｓ，Ｔｅｃｈｎｏｌｏｇｙ ａｎｄ Ａｐｐｌｉｃａｔｉｏｎｓ，Ｌ．Ａ．Ｈｏｒｎａｋ，ｅｄ．，Ｍａｒｃｅｌ Ｄｅｋｋｅｒ，Ｉｎｃ．（１９９２）；米国特許第５２９２６２０号および米国特許第５２１９７１０号で議論されており、その開示を参考のため本願に取り入れている。基本的には、本発明の記録材料は所望の導波管パターンで照射され、導波管パターンと周囲（被覆）の物質との間に屈折率コントラストを提供する。例えば集束レーザー光やマスクを非集束光源とともに用いることにより、露光を行うことが可能である。一般的に、一つの層がこのように露光され導波管パターンを提供し、被覆を完全にするためさらに層が追加され、導波管が完成する。このプロセスは、例えばＢｏｏｔｈ，ｓｕｐｒａ，２３５−３６ページや米国特許第５２９２６２０号の５および６段で議論されている。本発明の利点は、従来の成形技術を利用して、マトリックス硬化の前にマトリックス／光画像化システム混合物をさまざまな形状に成形できることである。例えば、マトリックス／光画像化システム混合物は、リッジ導波管に成形でき、それから屈折率パターンが成形構造に書き込まれる。したがって、ブラッグ格子などの構造を簡単に形成することができる。本発明の特徴は、このようなポリマー状導波管が有用である用途の幅を広げる。
【００３７】
以下の典型的な実施例により、本発明はさらに明確になるであろう。
【実施例】
比較例１
８９．２５重量％のフェノキシエチルアクリレート（光活性モノマー）、１０．１１重量％のエトキシ化ビスフェノールＡジアクリレート（光活性モノマー）、０．５重量％のＣｉｂａ ＣＧＩ−７８４（上記で説明済み）（光重合開始剤）および０．１４重量％のジブチルスズジラウリレート（マトリックス形成用の触媒）を含む溶液を調製した。０．０９０４ｇの溶液を、０．２７８４ｇのジイソシアネート末端ポリプロピレングリコール（分子量＝２４７１）（マトリックス前駆体）と０．０５ｇのα、ω−ジヒドロキシポリプロピレングリコール（分子量＝４２５）（マトリックス前駆体）を含む瓶に加えた。混合物を完全に混合し、光を遮蔽しながら室温で一晩重合させた。重合はイソシアネート基とヒドロキシル基の段階重合であり、ポリウレタンおよび溶解したアクリル酸エステルモノマーが生成した。前記混合物は何もつけていない目には透明に見えた。アクリル酸エステルモノマーの重合を開始する強いタングステンライトにあてると、前記物質は乳白色になり、ポリウレタンマトリックスとアクリル酸エステルポリマーが相溶性でないことを示した。
Ｋｒａｕｓｅから出版されている上述のポリマー混和性の表で調べてみると、ポリウレタンは、塩素化されたポリマーであるＳａｒａｎRと混和性、したがって相溶性であることが分かる。実施例１では、この情報を利用して作られた系を考慮する。
【００３８】
実施例１
９８．８６重量％の４−クロロフェニルアクリレートおよび１．１４重量％のジブチルスズジラウリレートを含む溶液を調製した。この溶液０．０１７ｇを、０．２５１９ｇのジイソシアネート末端ポリプロピレングリコール（分子量＝２４７１）、０．０４７ｇのα、ω−ジヒドロキシポリプロピレングリコール（分子量＝４２５）、０．０５１ｇの４−クロロフェニルアクリレートおよび０．０００６３ｇのＣｉｂａ ＣＧＩ−７８４（光重合開始剤）を含む瓶に加えた。この混合物を完全に混合し、光を遮蔽しながら室温で一晩重合させた。重合はイソシアネート基とヒドロキシル基の段階重合であり、ポリウレタンおよび溶解したクロロフェニルアクリレートモノマーが生成した。前記混合物は何もつけていない目には透明に見えた。アクリレートモノマーの重合を開始する強いタングステンライトにあてても、試料は透明のままであり、モノマーとマトリックスポリマーの相溶性を示した。
【００３９】
実施例２
０．００２６５ｇのＣｉｂａ ＣＧＩ−７８４を、０．２６２４８ｇのスチレン（光活性モノマー）に溶解させた。その溶液を、１．９１８７ｇのポリプロピレングリコールジグリシジルエーテル（分子量＝３８０）（ＰＰＧＤＧＥ）（マトリックス前駆体）、１．２４２８ｇのペンタエリスリトールテトラキス（メルカプトプロピオネート）（ＰＥＴＭＰ）（マトリックス前駆体）および０．１４４５ｇのトリス（２，４，６−ジメチルアミノメチル）フェノール（ＴＤＭＡＭＰ）（マトリックス形成の触媒）と混合した。前記溶液を、ガラススライド上で、厚さが約２００μｍで直径２５ｍｍのテフロンスペーサーの中へ分配し、別のガラススライドをその上にのせた。室温で約１時間放置の後、前記混合物は、メルカプタンとエポキシがアミンを触媒とした共重合を行ったため、ゲル化した。示差走査熱量測定法（ＤＳＣ）とフーリエ変換赤外分光法（ＦＴＩＲ）測定により、マトリックスの重合は２時間後たつと完全であることが分かった（すなわち、前駆体官能基が測定できるほどなかった）。スチレンモノマーと光重合開始剤を溶解しているエポキシ−メルカプタンマトリックスから成る、丈夫で弾性のある物質が得られた。その媒体の厚さは約２７０から２９０μｍであった。２４時間後、上述の米国特許第５７１９６９１号に記載の手順に準じて、一連の多重ホログラムが前記媒体に書き込まれた。１．７×１０^-3のΔｎが達成できた。ホログラフィ記録の後、異常な光散乱は検出されず、重合したスチレンモノマーとエポキシ−メルカプタンマトリックスの間に相溶性があることを示した。
【００４０】
実施例３
実施例２で作成した媒体のΔｎを増加させるため、ブロモスチレンモノマーを光活性モノマーとして使用した。０．０１２６２ｇのＣｉｂａ ＣＧＩ−７８４を、０．２１９４ｇの４−ブロモスチレン（光活性モノマー）に溶解させた。その溶液を、０．９５９７ｇのＰＰＧＤＧＥ，０．６０４２ｇのＰＥＴＭＰおよび０．０８４ｇのＴＤＭＡＭＰと混合した。実施例２と同様に試料を調製しホログラムを記録した。平均で４．２×１０^-3のΔｎが得られた。この場合でも、ホログラフィ記録の後に異常な光散乱は検出されず、さらにＤＳＣからは一つのガラス転移温度が示され、相溶性の系であることが示唆された。
【００４１】
実施例４
０．０５４ｇのＣｉｂａ ＣＧＩ−７８４を、０．４６ｇの４−ブロモスチレンに溶解させた。その溶液を、３．８ｇのＰＰＧＤＧＥ、２．４４ｇのＰＥＴＭＰおよび０．３ｇのＴＤＭＡＭＰと混合した。これは、実施例３で用いたブロモスチレンの半分の濃度に相当する。試料調製とホログラム記録は実施例２と同様に行った。Δｎは２．５×１０^-3であった。ブロモスチレンの重合により生じた厚さの減少（収縮）は約０．３％であった。光記録材料の弾性係数は約５．７×１０⁶Ｐａであった。
【００４２】
実施例５
４−メチルチオ−１−ビニルナフタレン（ＭＴＶＮ）（光活性モノマー）を以下の手順で合成した。
１−メチルチオナフタレンの調製：６３ｇ（０．２５モル）の１−ヨードナフタレンを窒素雰囲気下で１Ｌの無水エーテルに溶解させた。溶液を−７０℃まで冷却し、ヘキサン（０．２７モル）に溶解している２．５Ｍブチルリチウム（ＢｕＬｉ）１０９ｍＬを攪拌しながら３０分かけて添加した。２５ｇ（０．２７モル）のジメチルジスルフィドを添加し、４時間かけて室温に戻した。２００ｍＬの濃縮Ｎａ₂ＣＯ₃水溶液を添加し、有機層をＭｇＳＯ₄で乾燥し、濾過した後、濃縮して４２ｇ（９７％）の生成物と約１０ｇのヨウ化ブチル副生成物を含有する濃い橙色のオイルを得た。ガラス器具や他の装置は全て、残留スルフィドを分解するため漂白剤で洗浄した。
４−メチルチオ−１−ナフトアルデヒドの調製：１４．５ｇの１−メチルチオナフタレン（０．０８３モル）を、１２．４ｇ（０．１７モル）の無水Ｎ，Ｎ'−ジメチルホルムアミドと混合し、その溶液を氷浴で冷却した。２３．９ｇ（０．０９５モル）のジホスホリルテトラクロライドを攪拌しながら滴下し、温度を１５℃未満に保った。この混合物をゆっくりと１００℃まで加熱し、その温度で２時間攪拌を続けた。前記混合物を放冷し、氷浴で冷却した。２３ｇの水酸化ナトリウムを２００ｍＬの水に溶解した溶液（１００ｇの氷を加えて冷却）を前記反応混合物に注ぎ入れ、この混合物を攪拌しながら穏やかに４０℃まで加熱した。この時点で発熱反応が始まったので、加熱を中止し、温度を５０℃未満に保つためさらに氷を加えた。温度が３５℃未満で落ち着いたとき、２００ｍＬのエーテルを攪拌しながら添加した。有機層を分離し、水層をさらに１００ｍＬのエーテルで抽出した。合わせたエーテル抽出物をＭｇＳＯ₄で乾燥し、濾過し、濃縮し、１２０ｇのシリカゲルを用いたカラムクロマトグラフにかけ、それぞれ０，２５，５０，７５体積％のジクロロメタンを含むヘキサン各５００ｍＬで溶出させ、１００ｍＬの分画を集めた。生成物は、これらのうち６−８分画から集められ、黄色の固体９．８ｇ（５８％）が得られた。
【００４３】
４−メチルチオ−１−ビニルナフタレンの調製：１９．９ｇ（０．０５８モル）のメチルトリフェニルホスホニウムブロマイド粉末を１５０ｍＬの無水テトラヒドロフランに懸濁させた懸濁液を、窒素雰囲気下で攪拌しながら０℃に冷却した。ヘキサン（０．４８モル）中に溶解している１９ｍＬの２．５ＭのＢｕＬｉを、色をできるだけ薄く保ち、濃い橙色に着色するのを避けながら、３０分かけて添加した。この混合物を２５℃まで加熱し、この温度で１時間攪拌し、０℃に冷却した。２０ｍＬのテトラヒドロフランに溶解している９．８ｇの４−メチルチオ−１−ナフトアルデヒドを、０℃で攪拌しながら３０分かけて添加した。前記混合物を終夜攪拌し、室温まで温度を上げた。１０ｍＬのメタノールを加え、減圧下で溶媒を蒸発させた。残留分を、１００ｍＬのリグロイン（主にヘプタン）で、９０−１１０℃の沸点において５回抽出し、さらにメタノールを加えて残留分を柔らかく保った。抽出物を濾過し、濃縮し、４０ｇのシリカゲルを通してヘキサンで溶出させた。生成物は５００ｍＬの分画から得られ、６．８ｇの薄い黄色の液体（７０％）が得られ、−２０℃でオフホワイトの固体の形態で保存した。
媒体の調製：０．０５６２ｇのＣｉｂａ ＣＧＩ−７８４を、穏やかに加熱しながら０．１ｇの４−ブロモスチレンと０．４ｇのＭＴＶＮに加えた。その溶液を２．４ｇのＰＰＧＤＧＥ、１．５０８ｇのＰＥＴＭＰおよび０．２ｇのＴＤＭＡＭＰと混合した。試料調製とホログラム記録は実施例２および３と同様に行った。６．２×１０^-3という高いΔｎが、２００μｍの厚さで得られた。
【００４４】
実施例６
０．２６ｇのＣＧＩ−７８４光重合開始剤を、２．２２５ｇの４−ブロモスチレンに溶解させた。この溶液を、１９ｇのＰＰＧＤＧＥ、１２．２ｇのＰＥＴＭＰおよび０．３４ｇの１，８−ジアゾビシクロ［５．４．０．］ウンデカ−７−エン（ＤＢＵ）と混合した。この混合物は７分でゲル化し、マトリックス重合は１５分後に終了した。この媒体への多重ホログラム記録は成功した。
【００４５】
実施例７
材料の厚さが９４０μｍ（ガラススライドを含まず）である試料を以下のようにして調製した。０．７５ｇのＣｉｂａ ＣＧＩ−７８４を、穏やかに加熱しながら１．５０ｇのＭＴＶＮに加えた。その溶液を、９．０４ｇのＰＰＧＤＧＥ、５．６４ｇのＰＥＴＭＰおよび０．５６ｇのＴＤＭＡＭＰと混合した。１ｍｍまでの厚さの媒体を、上述のように真空ホルダーを用いて調製し、実施例２と同様にホログラムを記録した。Δｎを測定すると７．３×１０^-3であり、実質的にΔｎを保ったまま試料の厚さを大きくすることが可能であることが示された。
【００４６】
実施例８
異なる光活性モノマーの効果を比較するため５種の媒体を調製した。媒体は、材料の厚みが２５０μｍであり、以下のとおり調製した。
１） スチレン光活性モノマー：実施例２と同様に調製
２） ブロモスチレン光活性モノマー：実施例３と同様に調製
３） ブロモスチレンとＭＴＶＮ光活性モノマー：実施例５と同様に調製
４） ＭＴＶＮ光活性モノマー：実施例７と同様に調製
５） １−（３−ナフト−１−イルチオ）プロピルチオ）−４−ビニルナフタレン（ＮＴＰＶＮ）光活性モノマー：０．０２ｇのＣｉｂａ ＣＧＩ−７８４を、１．２００７ｇのＰＰＧＤＧＥに溶解させた。この溶液を０．４０８０ｇのＮＴＰＶＮ、０．７５２４ｇのＰＥＴＭＰおよび０．１３５８ｇのＴＤＭＡＭＰと混合した。試料を実施例２と同様に調製した。
３５の平面波ホログラムが、上述のホログラフィ装置を用いて、試料中で角度多重化された。書き込みの後、試料を投光露光し、残っている光活性種をすべて反応させた。屈折率コントラストが計算され、図２に（ベストフィットラインとともに）すぐ上に記した参照番号を用いて示してある。図２から、媒体１から５までで、比較的一定のレベルの寸法安定性を保ちながら（媒体の厚さの減少約０．３％）、約１．６×１０^-3から約９×１０^-3までの屈折率コントラストの増加が実現できたことが分かる。１−（３−ナフト−１−イルチオ）プロピルチオ）−４−ビニルナフタレンが屈折率コントラスト部分を２つ有すると仮定して、このモノマーを含有する媒体が示す屈折率の増加が期待される。
【００４７】
（ＮＴＰＶＮの調製は以下のとおりである。
１−（３−ナフト−１−イルチオ）プロピルチオ）ナフタレンの調製。２０．７ｇ（０．１モル）の１−ブロモナフタレンを２００ｍＬのエーテルに溶解させた溶液を攪拌しながら、−７８℃に冷却し、４０ｍＬのＢｕＬｉを加えた。温度を−２０℃まで上げ、再び−７８℃まで下げて、３．２ｇ（０．１モル）の硫黄を加えた。温度を１０℃まで上げ、再び−７８℃まで下げて、１４．８ｇ（０．０５モル）の１，３−ジヨードプロパンを加えた。室温まで暖めるにしたがって、ゆっくりした反応が薄層クロマトグラフィーにより示された。混合物を５０ｍＬのＴＨＦ存在下で還流しながら４時間加熱し、（冷却した後）水酸化ナトリウム水溶液と混合した。有機層をＭｇＳＯ₄で乾燥し、濾過し、濃縮し、１００ｇのシリカゲルを用い、０−３０％のジクロロメタンを含む２Ｌのヘキサンで溶出させながらクロマトグラフにかけた。９００ｍＬの生成物帯から５．５ｇの白色固体が得られ、ＮＭＲで純粋であると確認できた。
４−（３−ナフト−１−イルチオ）プロピルチオ）−１−ナフトアルデヒドの調製。上記生成物３．９ｇと１．４２ｇのジメチルホルムアミドを氷冷しながら混合し、その後２．８ｇのＰ₂Ｏ₃Ｃｌ₄を加えた。混合物を１００℃で２時間加熱し、室温に戻し、５０ｍＬの氷水に溶かした水酸化ナトリウム２．５ｇを加えて、４０℃に加熱し、室温で攪拌することにより加水分解した。有機物質が分散したときに、エーテルで抽出し、乾燥し、濾過し、濃縮し、７５０ｍＬのヘキサン−ジクロロメタン勾配の後ジクロロメタン中１０％の酢酸エチル（ＥｔＯＡｃ）を用いてクロマトグラフにかけた。２．０ｇの出発物質、１．３ｇの黄色油状生成物および０．２ｇのジアルデヒドが得られた。生成物の収率は３１％であり、または消費された出発物質を元に考えれば６３％である。
１−（３−ナフト−１−イルチオ）プロピルチオ）−４−ビニルナフタレンの調製。上記生成物１．３ｇをウィッティッヒ試薬（１．４ｇのメチルトリフェニルホスホニウムブロマイドおよび３０ｍＬのＴＨＦに溶かした３．３ミリモル（１当量）のＢｕＬｉを０℃から室温まで１時間かけて調製し、再び０℃に戻す）に加えた。室温で一晩攪拌した後、１．６ｍＬのメタノールを加え、溶液を濃縮して、ＭＴＶＮと同様にリグロインで抽出した。抽出物を一部濃縮し約１０ｍＬにして、ジクロロメタンで均一になるまで希釈し、２０ｇのシリカゲルのクロマトグラフにかけ、ヘキサン：ジクロロメタンの１：１溶液で溶出した。１．１ｇ（８４％）の粘度のある黄色の油が得られ、ＮＭＲにより純粋であると確認できた。真空で３０分乾燥した直後に、その物質を媒体調製用の混合物に混合した。本発明の実施態様は、本明細書の考察と本願で開示した本発明の実施より当業者には明らかであろう。
【図面の簡単な説明】
【図１】 基本的なホログラフィ記憶システムを示す図である。
【図２】記録媒体の屈折率コントラストに及ぼす、数種の異なる光活性モノマーの効果を示す図である。[0001]
[Reference to related applications]
This application is a continuation-in-part application of application number 09/046822 filed on March 24, 1998.
[0002]
BACKGROUND OF THE INVENTION
The present invention relates to an optical product including a holographic recording medium, and more particularly to a medium useful when used with a holographic recording system and a medium useful as an element such as an optical filter or a beam alignment body.
[0003]
[Prior art]
Developers of information storage devices and methods continue to seek increased storage capacity. As part of this development, so-called paged storage systems, in particular holographic systems, have been proposed as an alternative to conventional storage devices. The page-based system stores and reads out all two-dimensional displays of data such as pages. Typically, the recording light passes through a two-dimensional array of dark and transparent parts representing the data, and the holographic system is in three dimensions as a pattern of changing refractive index imprinted on the storage medium. Memorize the holographic display. Holographic systems are generally referred to as “Holographic Memories,”Scientific American, November 1995, the disclosure of which is incorporated herein by reference. One method of holographic storage is phase correlated multiplex holography, described in US Pat. No. 5,1969,691, issued February 17, 1998, the disclosure of which is incorporated herein by reference. In one embodiment of phase correlation multiplex holography, a reference beam passes through a phase mask and intersects an array displaying data and a signal beam passing through in a recording medium to form a hologram in the medium. The spatial relationship between the phase mask and the reference beam is adjusted for each successive page of data so that the phase of the reference beam is modulated and the data can be recorded in overlapping portions of the medium. The data is later reconstructed by passing the original recording location with the same phase modulation as that used for data recording. As a passive optical component that modulates or modifies light directed to the medium, for example, a volume hologram such as a filter or a beam alignment body can be used. An article such as a waveguide can also be formed by a writing process that causes a difference in refractive index.
[0004]
FIG. 1 shows a basic configuration of the holography system 10. System 10 includes a modulator 12, an optical recording medium 14, and a sensor 16. The modulation device 12 may be any device that can optically represent data in two dimensions. Device 12 is typically a spatial light modulator attached to an encoding unit that encodes data on the modulator. Based on the encoding, the device 12 selectively passes or blocks a portion of the signal beam 20 that passes through the device 12. In this way, the beam 20 is encoded with the data image. The image is stored at some location on or in the optical storage medium 14 by causing the coded signal beam 20 and reference beam 22 to interfere. This interference creates an interference pattern (ie, a hologram) and is stored as a pattern of refractive index that varies within the medium 14. It is also possible to store one or more holographic images in one place, or to store a plurality of holograms in an overlapping state by changing the angle, wavelength or phase of the reference beam 22 depending on the reference beam used. . The signal beam 20 typically passes through the lens 30 before intersecting the reference beam 22 within the medium 14. It is possible for the reference beam 22 to pass through the lens 32 before this intersection. Once the data is stored in the medium 14, it is possible to retrieve the data by crossing the reference beam 22 at the same location on the medium 14 at the same angle, wavelength or phase as during data storage. The reconstructed data passes through the lens 34 and is detected by the sensor 16. The sensor 16 is, for example, a charge coupled device or an active pixel sensor. The sensor 16 is typically attached to a unit that demodulates data.
[0005]
[Problems to be solved by the invention]
The capabilities of such holographic storage devices are limited in part by the storage medium. Iron doped lithium niobate has been used for many years as a storage medium for research purposes. However, lithium niobate is expensive and has poor sensitivity (1 J / cm²) And the refractive index contrast is low (Δn is about 10).^-Four), Indicates destructive reading (images are destroyed when reading). Alternatives to lithium niobate have been sought, particularly in the field of photosensitive polymer films. For example, W.W. K. Smoothers et al. , "Photopolymers for holography," SPIE OE / Laser Conference, 1212-03, Los Angeles, CA, 1990. The material described in this article contains a photoimaging system containing a liquid monomeric substance (photoactive monomer) and a photoinitiator (which is exposed to light to promote polymerization of the monomer) and photoimaging The system is an organic polymer host matrix that is substantially inert to light exposure. While writing information to the material (by passing the recording light through an array that displays the data), polymerization of the monomer occurs in the exposed areas. Due to the decrease in monomer concentration due to polymerization, the unexposed dark area monomer of the material diffuses into the exposed area. Polymerization and the resulting concentration gradient change the refractive index and form a hologram displaying the data. Unfortunately, a solvent must be used when depositing the preformed matrix material containing the photoimaging system on the substrate, and therefore, to obtain a stable material and reduce void formation, In order to fully evaporate, the material thickness is limited to, for example, less than about 150 μm. In the holographic process as described above that utilizes the three-dimensional space of the medium, the storage capacity is proportional to the thickness of the medium. Thus, the need for solvent removal reduces the storage capacity of the medium (this type of holography is generally referred to as volume holography because the Klein-Cook Q parameter is greater than 1 (W. Klein). and B. Cook, “Unified Approach to Ultrasonic Light Diffraction,”IEEE Transaction on Sonics and Ultrasonics, SU-14, 1967, at 123-134) In volume holography, the media thickness is generally larger than the fringe spacing).
[0006]
US patent application Ser. No. 08 / 698,142 (our reference Colvin-Harris-Katz-Schilling 1-2-16-10), the disclosure of which is incorporated herein by reference, is also photo-imaging in an organic polymer matrix. Although related to the system, thicker media can be produced. In particular, the above specification discloses a recording medium and an optical imaging system formed by polymerizing a matrix material as it is from a liquid mixture of organic oligomer matrix precursors. A similar system, but without an oligomer, is described in D.C. J. et al. Lounot et al. ,Pure and Appl. Optics2, 383 (1993). Since little or no solvent is required for the deposition of these matrix materials, larger thicknesses of, for example, 200 μm or more are possible. Although useful results are obtained from these processes, there is the potential for reaction of the matrix polymer precursor with the photoactive monomer. Such a reaction reduces the refractive index contrast between the matrix and the polymerized photoactive monomer, thereby affecting the intensity of the stored hologram.
[0007]
Thus, although progress has been made in producing optical recording media suitable for use in holographic storage systems, further progress is desired. In particular, media that can be made into relatively thick layers, such as layers greater than 200 μm, that substantially avoid reaction of the matrix material with the photoactive monomer and exhibit useful holographic properties are desired.
[0008]
[Means for Solving the Problems]
The present invention consists of improvements over conventional storage media. The present invention uses a matrix precursor (ie, one or more compounds that form the matrix) and a photoactive monomer that polymerizes in an independent reaction, so that the photoactive monomer and matrix precursor interact with each other during curing. Both reaction and subsequent inhibition of monomer polymerization can be substantially prevented. Also, phase separation can be substantially avoided because of the use of a matrix precursor and a photoactive monomer that form a compatible polymer. Moreover, since it forms as it is, the medium of desired thickness can be manufactured. Such material properties are useful in manufacturing a variety of optical products (optical products that utilize refractive index patterns or refractive index modulation to control or modify the light that is directed). Such optical products include, but are not limited to, optical waveguides, beam aligners and optical filters in addition to recording media. Independent reactions include (a) reactions that proceed with different types of reaction intermediates, such as ionic versus free radicals, and (b) the conditions under which the intermediate and matrix polymerize, both photoactive monomer functional groups, i.e. patterns Reactions that do not induce substantial polymerization of groups on the photoactive monomer that is the reaction site of the polymerization during the writing process (eg, hologram) (Substantial polymerization means more than 20% of the monomer functional groups) And (c) both the conditions under which the intermediate and the matrix polymerize may cause a non-polymerization reaction of the monomer functional group that causes the monomer functional group to interact with the matrix or subsequently inhibit the polymerization of the monomer functional group. It means a reaction that does not induce. The polymer is 7 × 10 with 90 ° light scattering of the polymer blend at the wavelength used for hologram formation.^-3cm^-1Less than Rayleigh ratio (R₉₀°), it is considered compatible. The Rayleigh ratio (Rθ) is a conventionally known characteristic. Kerker,The Scattering of Light and Other Electromagnetic Radiation, Academic Press, San Diego, 1969, at 38, the energy per steradian that is scattered in the direction θ by the unit volume when the medium is illuminated by unit intensity unpolarized light. The Rayleigh ratio is typically obtained by comparison with the energy scattering of a reference material with a known Rayleigh ratio. For example, polymers that are considered miscible by conventional tests, such as exhibiting a single glass transition temperature, are typically compatible. However, compatible polymers are not necessarily miscible. By intact means that the matrix is cured in the presence of the photoimaging system. Useful optical recording materials are obtained, i.e. matrix materials and photoactive monomers, photoinitiators, and / or other additives, which are formed to a thickness of more than 200 [mu] m, conveniently more than 500 [mu] m. Yes, when exposed to light, Rayleigh ratio, R₉₀, 7 × 10^-3Light projection properties can be shown (light projection exposure is incoherent light of a wavelength suitable for inducing substantially complete polymerization of the photoactive monomer of the entire material, optical recording Exposure of the entire material).
[0009]
The optical product of the present invention is formed by a process including mixing a matrix precursor and a photoactive monomer, curing the mixture, and forming the matrix as it is. As noted above, the reaction of the matrix precursor polymerizing during curing is independent of the reaction in which the photoactive monomer is later polymerized during writing of patterns, such as data or wave-conduit, and the matrix polymer and Polymers resulting from polymerization of photoactive monomers (hereinafter referred to as photopolymers) are compatible with each other (the matrix has an optical recording material of at least about 10^FiveIt is considered to be formed when exhibiting an elastic modulus of Pa. Curing refers to reacting the matrix precursor such that the matrix exhibits such an elastic modulus in the optical recording material). The optical product of the present invention contains a three-dimensionally crosslinked polymer matrix and one or more photoactive monomers. The at least one photoactive monomer contains, in addition to the monomer functionality, one or more moieties that are not substantially present in the polymer matrix (substantially absent is present in the matrix, ie, covalently bound). That part in the optically active material can be found in the photoactive monomer so that it is 20% or less). The independence of the host matrix and the monomer resulting from this makes it possible to form a modulation having a large refractive index without requiring useful recording characteristics of the holographic medium and high optical activity. Create desirable properties. Furthermore, the materials of the present invention can be formed without the disadvantageous solvent development previously required.
[0010]
In contrast to the holographic recording media of the present invention, media that use a matrix precursor and a photoactive monomer that polymerize by independent reactions react substantially between the precursor and the photoactive monomer during matrix curing. Often, a reaction (eg, greater than 20% of the monomer is bound to the matrix after curing) or other reaction that inhibits the polymerization of the photoactive monomer is experienced. The interaction tends to undesirably reduce the refractive index contrast between the matrix and the photoactive monomer, which may affect the subsequent polymerization of the photoactive monomer and clearly inhibits monomer polymerization. Affects the process. Regarding compatibility, previous work has been on photoactive monomers in matrix polymers, not on the compatibility of photopolymers formed within the matrix. However, if the photopolymer and the matrix polymer are not compatible, phase separation typically occurs during hologram formation. Such phase separation leads to an increase in light scattering reflected in the haze and opaque areas, thereby reducing the quality of the media and the fidelity with which the stored data is reproduced.
[0011]
For example, the optical product of the present invention, such as a holographic recording medium, is manufactured by a process comprising mixing a matrix precursor and a photoactive monomer and curing the mixture to form a matrix as it is. The matrix precursor and the photoactive monomer are (a) such that the reaction in which the matrix precursor polymerizes during curing is independent of the reaction in which the photoactive monomer polymerizes during writing, such as a pattern, and (b The matrix polymer and the polymer (photopolymer) resulting from the polymerization of the photoactive monomer are selected to be compatible with each other. As noted above, in addition to the optical recording material, i.e. the matrix material, at least about 10 photoactive monomers, photoinitiators and / or other additives are present.^FivePa, generally about 10^FiveAbout 10 from Pa⁹Pa, conveniently about 10⁶About 10 from Pa⁸It is considered that a matrix is formed when the elastic modulus of Pa is shown.
[0012]
Matrix polymer and photopolymer compatibility tends to prevent large (> 100 nm) phase separation of components, but such large phase separation can cause undesirable haze and opacity. Is typical. Use of photoactive monomers and matrix precursors that polymerize by independent reactions results in a cured matrix that is substantially non-interactive, ie, the photoactive monomer is substantially inert during matrix curing. Means that. Furthermore, the independent reaction does not inhibit the subsequent polymerization of the photoactive monomer. The at least one photoactive monomer contains, other than the monomer functionality, one or more portions that are substantially absent from the polymer matrix, that is, present in the matrix, ie, covalently bonded. That portion of the material can be found in the photoactive monomer so that it is 20% or less. The optical product thus obtained can exhibit a desirable refractive index because the matrix and the photoactive monomer are independent.
[0013]
As noted above, holograms, waveguides, and other optical products make use of the refractive index contrast (Δn) of the exposed and unexposed portions of the media, which contrast is at least partially monomeric. By diffusing into the exposed areas. When the refractive index contrast is high, the signal intensity is high when reading out the hologram, and the light wave in the waveguide is effectively restrained. Therefore, a high refractive index contrast is desirable. One method of providing a high refractive index contrast in the present invention is a portion that is substantially absent from the matrix and exhibits a refractive index substantially different from the refractive index exhibited by the majority of the matrix (hereinafter referred to as refractive). A photoactive monomer having a rate contrast portion). For example, it is mainly composed of a matrix containing aliphatic or saturated alicyclic moieties and containing low concentrations of heavy elements and conjugated double bonds (low refractive index), and mainly aromatic or similar high refractive index moieties. If a photoactive monomer is used, a high contrast will be obtained.
[0014]
The matrix is a solid polymer formed as it is from the matrix precursor by the curing step (curing refers to a step of inducing a reaction of the precursor to form a polymer matrix). The precursor may be one or more monomers, one or more oligomers or a mixture of monomers and oligomers. In addition, two or more precursor functional groups may be on one precursor molecule or on a group of precursor molecules (precursor functional groups are the reactive sites for polymerization during matrix curing, One or more groups on the precursor molecule). Conveniently, the precursor is a liquid at a temperature between about −50 ° C. and about 80 ° C. for better mixing with the photoactive monomer. It is also advantageous if the matrix polymerization can be performed at room temperature. Furthermore, it is advantageous if the polymerization can be carried out in less than 300 minutes, conveniently between 5 and 200 minutes. Glass transition temperature (T) of the optical recording material_gIt is advantageous if it is low enough so that the photoactive monomer can diffuse sufficiently and carry out a chemical reaction during the holographic recording process. In general, the T_gIs not more than 50 ° C. above the temperature at which the holographic recording takes place, ie in the case of a typical holographic recording, T_gIs about 80 ° C. to about −130 ° C. (measured by conventional methods). It would also be advantageous if the matrix could provide a desirable elastic modulus as described above by showing a three-dimensional network structure rather than a linear structure.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Examples of polymerization reactions contemplated for forming a matrix polymer in the present invention include cationic epoxy polymerization, cationic vinyl ether polymerization, cationic alkenyl ether polymerization, cationic allene ether polymerization, cationic ketene acetal polymerization, epoxy-amine step polymerization, epoxy -Mercaptan stage polymerization, unsaturated ester-amine stage polymerization (by Michael addition), unsaturated ester-mercaptan stage polymerization (by Michael addition), vinyl-silicon hydride stage polymerization (hydrosilylation), isocyanate-hydroxyl stage polymerization (urethane formation) ) And isocyanate-amine step polymerization (urea formation).
[0016]
The above reaction is enabled or facilitated by a suitable catalyst. For example, cationic epoxy polymerization is BF_Three, Which takes place rapidly at room temperature using other catalysts, other cationic polymerizations proceed in the presence of protons, the epoxy-mercaptan reaction and Michael addition are promoted by bases such as amines, and hydrosilylations are transition metals such as platinum. Fast progresses in the presence of the catalyst, and urethane and urea formation proceeds faster when tin catalysts are used. It is also possible to use a photogenerating catalyst for matrix formation if measures are taken to prevent polymerization of the photoactive monomer during photogeneration.
[0017]
The photoactive monomer can be polymerized by light, and can be any monomer, one type, or a plurality of types as long as it satisfies the polymerization conditions and compatibility requirements of the present invention together with the matrix material. Suitable photoactive monomers include monomers that polymerize by free radical reactions, such as acrylate, methacrylate, acrylamide, methacrylamide, styrene, substituted styrene, vinyl naphthalene, substituted vinyl naphthalene and other vinyl derivatives. There are molecules to contain. Free radical copolymer pair systems such as vinyl ether mixed with maleate and thiol mixed with olefin are also suitable. It is also possible to use cationic polymerization systems such as vinyl ethers, alkenyl ethers, allene ethers, ketene acetals and epoxies. It is also possible to use one photoactive monomer molecule containing two or more monomer functional groups. As noted above, a relatively high refractive index contrast is desired for the product of the present invention, whether to improve readout in a recording medium or to efficiently constrain light in a waveguide. In addition, it is convenient to induce such a relatively large refractive index change with a small amount of monomer functionality since the material generally shrinks when the monomer is polymerized (eg, in Examples 2 and 3 below). The shrinkage caused by writing by hologram recording is approximately 0.7%, but the concentration of photoactive monomer was reduced in Example 4, but the shrinkage caused by writing was correspondingly reduced (0.30 to 0.35). %)). Such shrinkage adversely affects the retrieval of data from stored holograms and degrades the performance of the waveguide element, such as by increasing transmission loss and other performance deflections. Therefore, it is desirable to reduce the number of monomer functional groups that are polymerized to obtain the required refractive index contrast. If the ratio of the molecular volume of the monomer to the number of monomer functional groups in the monomer is increased, the number of monomer functional groups can be reduced. To increase the ratio, a large refractive index contrast portion and / or a large amount of refractive index contrast portion may be incorporated into the monomer. For example, if the matrix is primarily composed of aliphatic or other low refractive index moieties and the monomer is a species with a higher index of refraction imparted by a benzene ring, incorporate a naphthalene ring instead of a benzene ring (Naphthalene ring has a large volume) By incorporating one or more benzene rings, the molecular volume can be increased with respect to the number of monomer functional groups without increasing the number of monomer functional groups. it can. In this way, less monomer functional groups are required to polymerize monomers having a larger molecular volume / monomer functional group ratio and a certain volume fraction, thereby reducing shrinkage. However, the required volume fraction of monomer diffuses from the unexposed area to the exposed area, providing the desired refractive index.
[0018]
However, the molecular volume of the monomer should not be so great as to slow the diffusion below an acceptable rate. The diffusion rate is controlled by factors such as the size of the diffusing chemical species, the viscosity of the medium and intermolecular interactions. Large species tend to diffuse slowly, but it may be possible to reduce the viscosity or adjust to other molecules to increase the diffusion to an acceptable level. It is also important that such large molecules remain compatible with the matrix, consistent with the discussion in this application.
[0019]
Numerous structures are possible for monomers containing multiple refractive index contrast moieties. For example, the moiety can be present in the main chain of the linear oligomer or can be a substituent along the oligomer chain. Alternatively, the refractive index contrast portion can be a branched or dendritic low molecular weight oligomer subunit.
[0020]
In addition to the photoactive monomer, the optical product typically contains a photoinitiator (the photoinitiator and photoactive monomer are part of the overall photoimaging system). The photoinitiator chemically initiates the polymerization of the monomer when exposed to relatively low levels of recording light, thus avoiding the need for direct photoinduced polymerization of the monomer. Photoinitiators are generally a source of chemical species that initiate the polymerization of a particular photoactive monomer. Typically, 0.1 to 20 weight percent photoinitiator, based on the weight of the photoimaging system, provides desirable results.
[0021]
Various photoinitiators known to those skilled in the art and commercially available are suitable for use in the present invention. Photopolymerization initiators sensitive to light in the visible light region, in particular conventional laser sources such as Ar⁺(458, 488, 514 nm) and He-Cd laser (442 nm) blue and green lines, frequency doubled YAG laser (532 nm). He-Ne (633 nm) and Kr⁺It is advantageous to use a photoinitiator that is sensitive to light of a wavelength such as the red line of the laser (647 and 676 nm). Convenient free radical initiators include bis (η-5-2,4-cyclopentadien-1-yl) bis [2,6-difluoro-3- (1H-pyrrole), commercially available from Ciba as CGI-784. -1-yl) phenyl] titanium. Another visible light free radical initiator (requires coinitiator) is 5,7-diiodo-3-butoxy-6-fluorone, commercially available as H-Nu470 from Spectra Group Limited. A free radical photopolymerization initiator based on a dye-hydrogen donor system can also be used. Examples of suitable dyes are eosin, rose bengal, erythrosine and methylene blue, and suitable hydrogen donors are quaternary amines such as n-methyldiethanolamine. In the case of a cationic polymerization monomer, a cationic photopolymerization initiator such as a sulfonium salt or an iodonium salt is used. Since these cationic photopolymerization initiator salts mainly absorb light in the ultraviolet region, it is typical to use light in the visible region with increased photosensitivity by the dye. Another visible range cationic photoinitiator is commercially available from Ciba as Iglacur 261 (η_Five-2,4-cyclopentadien-1-yl) (η₆-Isopropylbenzene) -iron (II) hexafluorophosphate. It is contemplated that other additives may be used in the optical imaging system, such as inert diffusing agents that exhibit a relatively high or low refractive index.
[0022]
For holographic recording, it is advantageous for the matrix to be a polymer formed by mercaptan-epoxy step polymerization, and more advantageously if it is a polymer formed by mercaptan-epoxy step polymerization and having a polyether backbone. The polyether backbone provides the desired compatibility with several useful photoactive monomers, particularly vinyl aromatic compounds. Specifically, a photopolymerizable monomer selected from styrene, bromostyrene, divinylbenzene and 4-methylthio-1-vinylnaphthalene (MTVN) is formed by a mercaptan-epoxy step polymerization and is a matrix polymer having a polyether skeleton. It has been found useful for use with. A monomer having two or more refractive index parts and useful for use with these polyether matrix polymers is 1- (3-naphth-1-ylthio) propylthio) -4-vinylnaphthalene.
[0023]
Due to the independence, the respective polymerization reactions of the matrix precursor and the photoactive monomer are (a) the reaction proceeds with different types of reaction intermediates, and (b) both the conditions under which the intermediate and matrix are polymerized. , Does not induce substantial polymerization of the photoactive monomer functional group, and (c) both the intermediate and the conditions under which the matrix is polymerized can cause an interaction (reaction between the monomer functional group and the matrix polymer), Thereafter, it is selected so as not to induce a non-polymerization reaction of the monomer functional group which inhibits the polymerization of the monomer functional group. According to paragraph (a), if the matrix is polymerized by the use of an ionic intermediate, it may be appropriate to polymerize the photoactive monomer using a free radical reaction. However, according to (b), the ionic intermediate must not induce substantial polymerization of the photoactive monomer functional group. Again, according to paragraph (b), for example, it is noted that free radical matrix polymerization initiated by light typically induces cationic polymerization of photoactive monomer functional groups initiated by light. There must be. In other cases, two independent reactions are not independent for the purposes of the present invention if both proceed according to a single reaction condition. According to paragraph (c), for example, matrix polymerization catalyzed by a base may cause a non-polymerization reaction when the photoactive monomer functional group reacts with the base, although the polymerization of the monomer functional group may occur by an independent reaction. Should not be implemented. As a specific example, base-catalyzed epoxy-mercaptan polymerization cannot be performed with acrylate monomers, but this is because acrylates polymerize by free radical reactions, but acrylates are base-catalyzed. This is because it reacts with mercaptan in the presence to form an interaction.
[0024]
Table 1 below shows the matrix / photoactive monomer combinations when the matrix polymerization reaction and the photoactive monomer polymerization can be performed independently and when both polymerization reactions interfere with each other (the photoactive monomer is in the lateral direction, the matrix polymer “X” indicates a monomer reaction during an interreaction or matrix polymerization, “O” indicates an independent reaction, “I” indicates a group in which the photoactive monomer functional group does not polymerize. Polymerization of the photoactive monomer is hindered by reagents or reactions that form the polymeric matrix, such as in the case of transformations, or when there are species that reduce the rate or yield of monomer functional groups after matrix cure. ).
[0025]
[Table 1]

[0026]
For the purposes of the present invention, a blend of polymers is 7 × 10 with 90 ° light scattering.^-3cm^-1Less than Rayleigh ratio (R₉₀°), the polymer is considered compatible. The Rayleigh ratio, Rθ, is a conventionally known characteristic. Kerker,The Scattering of Light and Other Electromagnetic Radiation, Academic Press, San Diego, 1969, the energy scattered per unit steradian by the unit volume in direction θ when the medium is illuminated by unit intensity unpolarized light. The light source used for the measurement is generally a laser having a wavelength in the visible region. Usually, the wavelength used for hologram writing is used. The scattering measurement is performed on the optical recording material subjected to the projection exposure. The scattered light is collected at a 90 ° angle from the incident light, typically by a photodetector. Although it is possible to place a narrow band filter centered on the laser wavelength in front of the photodetector to block the fluorescence, such a means is not necessary. The Rayleigh ratio is typically obtained by comparison with the energy scattering of a reference material with a known Rayleigh ratio.
[0027]
Polymer blends that are considered miscible by conventional testing methods, such as exhibiting a single glass transition temperature, are typically also compatible, ie miscibility is part of compatibility. Standard miscibility guidelines and tables are therefore useful in selecting compatible blends. However, immiscible polymer blends may be compatible by the light scattering test described above.
[0028]
The polymer blend has a single glass transition temperature, T, as measured by conventional methods._g, Is generally considered miscible. The immiscible blend is the T of each polymer._gTypically, two glass transition temperatures corresponding to the values are shown. T_gThe test was performed as a step change in heat flow (usually the vertical axis)._gIt is common practice to use differential scanning calorimetry (DSC). Reported T_gIs the temperature at which the vertical axis reaches the midpoint value of the extrapolated baseline before and after the transition. T_gIt is also possible to use dynamic mechanical analysis (DMA) to measure. DMA can measure the storage modulus of a material, which drops several orders of magnitude in the glass transition region. T polymers close to each other in the blend_gMay have. In such cases, Brinke et al. , “The thermal charactarization of multi-component systems by enhancement relaxation,”Thermochimica Acta. , 238 (1994), at 75, and overlapping T using conventional methods._gShould be separated.
[0029]
The miscible matrix polymer and photoactive monomer can be selected in several ways. For example, O.D. Olabisi et al. ,Polymer-Polymer Miscibility, Academic Press, New York, 1979; M.M. Robeson,MMI. Press Symp. Ser., 2, 177, 1982; A. Utracki,Polymer Alloys and Blends: Thermodynamics a nd Rheology, Hanser Publishers, Munich, 1989; Krause inPolymer Handbook, J .; Brandup and E.M. H. Immergut, Eds. , 3rd Ed. , Wiley Interscience, New York, 1989, pp. Although several published compilations of miscible polymers are available, such as VI347-370, the disclosure of the above materials is incorporated herein by reference. Even if the desired polymer is not found in such references, a specific technique can be used to determine compatible optical recording materials using a control sample.
[0030]
The determination of miscible or compatible blends is further aided by considering intermolecular interactions that generally promote miscibility. For example, polystyrene and poly (methyl vinyl ether) are well known to be miscible due to the attractive interactions between the methyl ether group and the phenyl ring. Thus, by using methyl ether groups in one polymer and phenyl groups in another polymer, it is possible to increase the miscibility or at least the compatibility of the two polymers. It has been shown that non-miscible polymers can be made miscible by incorporating appropriate functional groups that provide ionic interactions (Z.L.Zhou and A. Eisenberg, J. et al. Polym. Sci. , Polym. Phys. Ed., 21 (4), 595, 1983; Muraliand A.M. Eisenberg,J. et al. Polym. Sci. , Part B: Polym. Phys., 26 (7), 1385, 1988; and A Natansohn et al. ,Makromol. Chem. , Macromol. Symp., 16, 175, 1988). For example, polyisoprene and polystyrene are immiscible. However, when polyisoprene is partially (5%) sulfonated and 4-vinylpyridine is copolymerized with polystyrene, the blend of these functional polymers becomes miscible. It is believed that the ionic interaction between the sulfonated group and the pyridine group (proton transfer) is the driving force that makes this blend miscible. Similarly, polystyrene and poly (ethyl acrylate), which are normally immiscible, become miscible when the polystyrene is slightly sulfonated (R.E. Taylor-Smith and R.A. Register,Macromolecules, 26, 2802, 1993). Charge transfer has also been utilized to render immiscible polymers miscible. For example, poly (methyl acrylate) and poly (methyl methacrylate) are immiscible, but poly (methyl acrylate) is copolymerized with (N-ethylcarbazol-3-yl) methyl acrylate (electron donor). When poly (methyl methacrylate) is copolymerized with 2-[(3,5-dinitrobenzoyl) oxy] ethyl methacrylate (electron acceptor), using appropriate amounts of donor and acceptor, the blend of these polymers is Become miscible (M.C. Piton and A. Nattansohn,Macromolecules, 28, 15, 1995). Poly (methyl methacrylate) and polystyrene can also be made miscible using the corresponding donor-acceptor comonomer (MC Piton and A. Nattansohn,Macromolecules, 28, 1605, 1995).
[0031]
A. Hale and H.M. Bair, Ch. 4- "Polymer Blends and Block Copolymers,"Thermal Characteristic of Polymeric Materials, 2nd Ed. , Academic Press, 1997, as considered in a recent overview, there are various types of polymer miscibility or compatibility testing methods. For example, in the area of optical methods, opacity typically represents a material composed of two layers, and transparency generally represents a miscible system. Other methods for assessing miscibility include neutron scattering, infrared spectroscopy (IR), nuclear magnetic resonance (NMR), x-ray scattering and diffraction, fluorescence, Brillouin scattering, melt titration, calorimetry, and chemiluminescence. is there. For example, L.M. Robeson,supra,; Krause,Chemtracts-Macromol. Chem., 2, 367, 1991a; Veselly inPolymer Blends and Alloys, M.M. J. et al. Folkes and P.M. S. Hope, Eds. Blackie Academic and Professional, Glasgow, pp. 103-125; M.M. Coleman et al. ,Specific Interactions and the Miscibility of Polymer Blends, Technological Publishing, Lancaster, PA, 1991; Garton,Infrared Spectroscopyof Polymer Blends, Composites and SurfacesHanser, New York, 1992; W. Kelts et al. ,Macmolecules, 26, 2941, 1993; L. White and P.M. A. Mirau,Macmolecules, 26, 3049, 1993; L. White and P.M. A. Mirau,Macmolecules27, 1648, 1994; A. Cruz et al. ,Macmolecules, 12, 726, 1979; C.I. J. et al. Landry et al. ,Macmolecules26, 35, 1993.
[0032]
By incorporating reactive groups into the polymer matrix, the compatibility of incompatible polymers has been increased if such groups can react with the photoactive monomer during the holographic recording process. A portion of the photoactive monomer is thus grafted onto the matrix during recording. If these grafts are sufficient, it is possible to prevent or reduce phase separation during recording. However, when the refractive index of the grafted part and the monomer are relatively similar, too much grafting will undesirably reduce the refractive index contrast if, for example, more than 30% of the monomer is grafted onto the matrix Will let you.
[0033]
The holographic recording medium of the present invention is formed by appropriately supporting an optical recording material so that holographic writing and reading can be performed. Typically, the production of the media consists of depositing the matrix precursor / photoimaging system mixture between two plates, for example using a gasket to contain the mixture. The plate is typically glass, but it is also possible to use a material that is transparent to the radiation used to write the data, such as a plastic such as polycarbonate or poly (methyl methacrylate). It is also possible to put a spacer between the plates to keep the desired thickness of the recording medium. During matrix curing, the material can shrink and stress the plate, but such stress changes the parallelism and / or spacing of the plate and impairs the optical properties of the media. To reduce such effects, it is useful to place the plate in a device with a mount, such as a vacuum chuck, that can be adjusted to accommodate changes in parallelism and / or spacing. In such an apparatus, the parallelism can be observed in real time by a conventional interferometric method, and necessary adjustments can be made during curing. Such devices are discussed, for example, in US patent application Ser. No. 08 / 867,563 (our reference number Campbell-Harris-Levinos 3-5-3), the disclosure of which is incorporated herein by reference. The optical recording material of the present invention can be supported by other methods. For example, it may be envisaged that the matrix precursor / photoimaging system mixture is applied to the pores of a substrate, such as a microporous glass material such as Vycor, prior to matrix curing. Conventional polymer processing such as hermetic molding and plate extrusion is also conceivable. A layered medium, i.e. a medium having a plurality of substrates, e.g. glass, with an optical recording material deposited therebetween is also conceivable.
[0034]
The media of the present invention can be used in holographic systems as described above. The amount of information that can be stored in the holographic medium is proportional to the product of the refractive index contrast Δn of the optical recording material and the thickness of the optical recording material, d (refractive index contrast, Δn is conventionally known, and the volume hologram of a plane wave is Defined as the magnitude of the sinusoidal variation of the refractive index of the material being written, where n (x) = n₀+ Δn cos (K_x) Where n (x) is a spatially varying refractive index, x is a position vector, K_xIs the lattice wave vector and n₀Is the baseline refractive index of the medium. For example, P.I. Hariharan,Optical holography: Principles, Techniques, and Applications, Cambridge University Press, Cambridge, 1991, at44). The Δn of the material is typically calculated from the diffraction efficiency of a single volume hologram or multiple sets of volume holograms recorded on the medium. The Δn is related to the medium before writing, but is observed by measurement performed after recording. The optical recording material of the present invention is 3 × 10^-3It is convenient to show the above Δn.
[0035]
Examples of other optical products include beam filters, beam aligners, deflectors and optical couplers (see, for example, L. Solidmar and D. Cooke,Volume Holography and Volume Grattings, Academic Press, 315-327 (1981). The disclosure of this document is incorporated herein for reference). The beam filter separates a part of incident laser light flying at a certain angle from other light. Specifically, the Bragg selectivity of a thick transmission hologram selectively diffracts light incident at a specific angle, and light coming from other angles passes through the hologram without being deflected (J.E. Ludman et al., “Very thick holographic nonspatial filtering of laserbeams,”Optical Engineering, Vol. 36, no. 6, 1700 (1997). The disclosure of this document is incorporated herein for reference). The beam alignment body is a hologram that deflects light incident at a Bragg angle. An optical coupler is typically a combination of beam polarizers that direct light from a light source to a target. These products, commonly referred to as holographic optical elements, are manufactured by creating specific optical interference patterns in a recording medium, as described above with respect to data storage. Media for these holographic optical elements can be manufactured by the techniques described herein with respect to recording media and waveguides.
[0036]
As described above, the material principles described herein apply not only to hologram formation, but also to the formation of optical transmission elements such as waveguides. The polymer optical waveguide is, for example, B.I. L. Booth, “Optical Interconnection Polymers,” inPolymers for Lightwave and Integrated Optics, Technology and ApplicationsL. A. Hornak, ed. , Marcel Dekker, Inc. (1992); U.S. Pat. No. 5,292,620 and U.S. Pat. No. 5,219,710, the disclosures of which are incorporated herein by reference. Basically, the recording material of the present invention is illuminated with a desired waveguide pattern, providing a refractive index contrast between the waveguide pattern and the surrounding (coating) material. For example, exposure can be performed by using a focused laser beam or a mask together with a non-focused light source. In general, one layer is thus exposed to provide a waveguide pattern, and additional layers are added to complete the coating, completing the waveguide. This process is for example Boot,supraPp. 235-36 and U.S. Pat. No. 5,292,620, stages 5 and 6. An advantage of the present invention is that the matrix / photoimaging system mixture can be molded into various shapes prior to matrix curing using conventional molding techniques. For example, the matrix / photoimaging system mixture can be molded into a ridge waveguide, and then the refractive index pattern is written into the molded structure. Therefore, a structure such as a Bragg grating can be easily formed. The features of the present invention broaden the range of applications in which such polymeric waveguides are useful.
[0037]
The invention will be further clarified by the following exemplary examples.
【Example】
Comparative Example 1
89.25 wt% phenoxyethyl acrylate (photoactive monomer), 10.11 wt% ethoxylated bisphenol A diacrylate (photoactive monomer), 0.5 wt% Ciba CGI-784 (described above) ( A solution containing a photoinitiator) and 0.14% by weight dibutyltin dilaurate (catalyst for matrix formation) was prepared. 0.0904 g of solution containing 0.2784 g diisocyanate-terminated polypropylene glycol (molecular weight = 2471) (matrix precursor) and 0.05 g α, ω-dihydroxypolypropylene glycol (molecular weight = 425) (matrix precursor) Added to. The mixture was mixed thoroughly and allowed to polymerize overnight at room temperature with light shielding. The polymerization was a step polymerization of isocyanate groups and hydroxyl groups, producing polyurethane and dissolved acrylate monomer. The mixture appeared clear to the eyes without anything. When exposed to a strong tungsten light that initiates polymerization of the acrylate monomer, the material turned milky white indicating that the polyurethane matrix and the acrylate polymer were not compatible.
Examining the above-mentioned polymer miscibility table published by Krause reveals that polyurethane is miscible and thus compatible with the chlorinated polymer Saran®. Example 1 considers a system created using this information.
[0038]
Example 1
A solution containing 98.86 wt% 4-chlorophenyl acrylate and 1.14 wt% dibutyltin dilaurate was prepared. 0.017 g of this solution was added to 0.2519 g diisocyanate-terminated polypropylene glycol (molecular weight = 2471), 0.047 g α, ω-dihydroxypolypropylene glycol (molecular weight = 425), 0.051 g 4-chlorophenyl acrylate and 0.00063 g. Of Ciba CGI-784 (photoinitiator). This mixture was thoroughly mixed and allowed to polymerize overnight at room temperature while shielding light. The polymerization was a step polymerization of isocyanate and hydroxyl groups, producing polyurethane and dissolved chlorophenyl acrylate monomer. The mixture appeared clear to the eyes without anything. Even when exposed to strong tungsten light that initiates polymerization of the acrylate monomer, the sample remained transparent, indicating compatibility of the monomer with the matrix polymer.
[0039]
Example 2
0.00265 g of Ciba CGI-784 was dissolved in 0.26248 g of styrene (photoactive monomer). The solution was transferred to 1.9187 g of polypropylene glycol diglycidyl ether (molecular weight = 380) (PPGDGE) (matrix precursor), 1.2428 g of pentaerythritol tetrakis (mercaptopropionate) (PETMP) (matrix precursor) and 0 Mixed with 1445 g of tris (2,4,6-dimethylaminomethyl) phenol (TDMPAMP) (catalyst for matrix formation). The solution was dispensed on a glass slide into a Teflon spacer having a thickness of about 200 μm and a diameter of 25 mm, and another glass slide was placed thereon. After standing at room temperature for about 1 hour, the mixture gelled because mercaptan and epoxy were copolymerized with amine as a catalyst. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) measurements showed that the polymerization of the matrix was complete after 2 hours (ie, there was not enough precursor functionality to be measured). ). A tough and elastic material consisting of an epoxy-mercaptan matrix in which styrene monomer and photoinitiator were dissolved was obtained. The media thickness was about 270 to 290 μm. After 24 hours, a series of multiple holograms was written on the medium according to the procedure described in US Pat. 1.7 × 10^-3Of Δn could be achieved. No anomalous light scattering was detected after holographic recording, indicating compatibility between the polymerized styrene monomer and the epoxy-mercaptan matrix.
[0040]
Example 3
In order to increase the Δn of the media prepared in Example 2, bromostyrene monomer was used as the photoactive monomer. 0.01262 g of Ciba CGI-784 was dissolved in 0.2194 g of 4-bromostyrene (photoactive monomer). The solution was mixed with 0.9597 g PPGDGE, 0.6042 g PETMP and 0.084 g TDAMP. A sample was prepared and a hologram was recorded in the same manner as in Example 2. 4.2 × 10 on average^-3Of Δn was obtained. Even in this case, abnormal light scattering was not detected after holographic recording, and DSC showed one glass transition temperature, suggesting a compatible system.
[0041]
Example 4
0.054 g Ciba CGI-784 was dissolved in 0.46 g 4-bromostyrene. The solution was mixed with 3.8 g PPGDGE, 2.44 g PETMP and 0.3 g TDAMP. This corresponds to half the concentration of bromostyrene used in Example 3. Sample preparation and hologram recording were performed in the same manner as in Example 2. Δn is 2.5 × 10^-3Met. The thickness reduction (shrinkage) caused by the polymerization of bromostyrene was about 0.3%. The elastic coefficient of the optical recording material is about 5.7 × 10⁶Pa.
[0042]
Example 5
4-Methylthio-1-vinylnaphthalene (MTVN) (photoactive monomer) was synthesized by the following procedure.
Preparation of 1-methylthionaphthalene: 63 g (0.25 mol) of 1-iodonaphthalene was dissolved in 1 L of anhydrous ether under nitrogen atmosphere. The solution was cooled to −70 ° C., and 109 mL of 2.5 M butyllithium (BuLi) dissolved in hexane (0.27 mol) was added over 30 minutes with stirring. 25 g (0.27 mol) of dimethyl disulfide was added and allowed to warm to room temperature over 4 hours. 200 mL concentrated Na₂CO_ThreeAqueous solution is added and the organic layer is MgSO 4_Four, Filtered and concentrated to a dark orange oil containing 42 g (97%) of product and about 10 g of butyl iodide byproduct. All glassware and other equipment was washed with bleach to decompose residual sulfide.
Preparation of 4-methylthio-1-naphthaldehyde: 14.5 g 1-methylthionaphthalene (0.083 mol) is mixed with 12.4 g (0.17 mol) anhydrous N, N′-dimethylformamide, The solution was cooled with an ice bath. 23.9 g (0.095 mol) of diphosphoryl tetrachloride was added dropwise with stirring to keep the temperature below 15 ° C. The mixture was slowly heated to 100 ° C. and stirring was continued at that temperature for 2 hours. The mixture was allowed to cool and cooled in an ice bath. A solution of 23 g of sodium hydroxide in 200 mL of water (cooled by adding 100 g of ice) was poured into the reaction mixture, and the mixture was gently heated to 40 ° C. with stirring. At this point, an exothermic reaction began, so heating was stopped and more ice was added to keep the temperature below 50 ° C. When the temperature settled below 35 ° C., 200 mL of ether was added with stirring. The organic layer was separated and the aqueous layer was further extracted with 100 mL ether. The combined ether extracts are MgSO_Four, Filtered, concentrated, and column chromatographed using 120 g of silica gel, eluting with 500 mL of hexane each containing 0, 25, 50, and 75 vol% dichloromethane to collect 100 mL fractions. The product was collected from these 6-8 fractions to give 9.8 g (58%) of a yellow solid.
[0043]
Preparation of 4-methylthio-1-vinylnaphthalene: A suspension obtained by suspending 19.9 g (0.058 mol) of methyltriphenylphosphonium bromide powder in 150 mL of anhydrous tetrahydrofuran was stirred while stirring under a nitrogen atmosphere. Cooled to ° C. 19 mL of 2.5 M BuLi dissolved in hexane (0.48 mol) was added over 30 minutes keeping the color as light as possible and avoiding a dark orange coloration. The mixture was heated to 25 ° C., stirred at this temperature for 1 hour, and cooled to 0 ° C. 9.8 g of 4-methylthio-1-naphthaldehyde dissolved in 20 mL of tetrahydrofuran was added over 30 minutes with stirring at 0 ° C. The mixture was stirred overnight and allowed to warm to room temperature. 10 mL of methanol was added and the solvent was evaporated under reduced pressure. The residue was extracted 5 times with 100 mL ligroin (mainly heptane) at a boiling point of 90-110 ° C. and further methanol was added to keep the residue soft. The extract was filtered, concentrated and eluted through 40 g of silica gel with hexane. The product was obtained from a 500 mL fraction and 6.8 g of a pale yellow liquid (70%) was obtained and stored at −20 ° C. in the form of an off-white solid.
Media preparation: 0.0562 g Ciba CGI-784 was added to 0.1 g 4-bromostyrene and 0.4 g MTVN with gentle heating. The solution was mixed with 2.4 g PPGDGE, 1.508 g PETMP and 0.2 g TDAMP. Sample preparation and hologram recording were performed in the same manner as in Examples 2 and 3. 6.2 × 10^-3A high Δn of 200 μm was obtained.
[0044]
Example 6
0.26 g of CGI-784 photoinitiator was dissolved in 2.225 g of 4-bromostyrene. This solution was added to 19 g of PPGDGE, 12.2 g of PETMP and 0.34 g of 1,8-diazobicyclo [5.4.0. It was mixed with undeca-7-ene (DBU). The mixture gelled in 7 minutes and the matrix polymerization was complete after 15 minutes. Multiple hologram recording on this medium was successful.
[0045]
Example 7
A sample having a material thickness of 940 μm (not including a glass slide) was prepared as follows. 0.75 g Ciba CGI-784 was added to 1.50 g MTVN with gentle heating. The solution was mixed with 9.04 g PPGDGE, 5.64 g PETMP and 0.56 g TDAMP. Media with a thickness of up to 1 mm were prepared using a vacuum holder as described above, and holograms were recorded as in Example 2. When Δn is measured, 7.3 × 10^-3It was shown that it is possible to increase the thickness of the sample while substantially maintaining Δn.
[0046]
Example 8
Five media were prepared to compare the effects of different photoactive monomers. The medium had a material thickness of 250 μm and was prepared as follows.
1) Styrene photoactive monomer: prepared as in Example 2
2) Bromostyrene photoactive monomer: prepared as in Example 3
3) Bromostyrene and MTVN photoactive monomer: prepared as in Example 5
4) MTVN photoactive monomer: prepared as in Example 7
5) 1- (3-Naphtho-1-ylthio) propylthio) -4-vinylnaphthalene (NTPVN) photoactive monomer: 0.02 g Ciba CGI-784 was dissolved in 1.2007 g PGDGE. This solution was mixed with 0.4080 g NTPVN, 0.7524 g PETMP and 0.1358 g TDAMP. Samples were prepared as in Example 2.
35 plane wave holograms were angle multiplexed in the sample using the holography apparatus described above. After writing, the sample was exposed to light and allowed to react with all remaining photoactive species. Refractive index contrast was calculated and is shown in FIG. 2 using the reference numbers immediately above (along with the best fit line). From FIG. 2, while maintaining a relatively constant level of dimensional stability from media 1 to 5 (approximately 0.3% reduction in media thickness), approximately 1.6 × 10^-3To about 9 × 10^-3It can be seen that an increase in refractive index contrast was achieved. Assuming that 1- (3-naphth-1-ylthio) propylthio) -4-vinylnaphthalene has two refractive index contrast moieties, an increase in the refractive index exhibited by the medium containing this monomer is expected.
[0047]
(The preparation of NTPVN is as follows.
Preparation of 1- (3-naphth-1-ylthio) propylthio) naphthalene. While stirring a solution of 20.7 g (0.1 mol) of 1-bromonaphthalene in 200 mL of ether, the solution was cooled to −78 ° C., and 40 mL of BuLi was added. The temperature was raised to −20 ° C. and again to −78 ° C., and 3.2 g (0.1 mol) of sulfur was added. The temperature was raised to 10 ° C, again lowered to -78 ° C, and 14.8 g (0.05 mole) of 1,3-diiodopropane was added. Slow reaction was shown by thin layer chromatography as it warmed to room temperature. The mixture was heated at reflux in the presence of 50 mL THF for 4 hours and (after cooling) mixed with aqueous sodium hydroxide. The organic layer is MgSO_FourDried, filtered, concentrated, and chromatographed using 100 g of silica gel, eluting with 2 L of hexane containing 0-30% dichloromethane. 5.5 g of white solid was obtained from 900 mL of product band and confirmed to be pure by NMR.
Preparation of 4- (3-naphth-1-ylthio) propylthio) -1-naphthaldehyde. 3.9 g of the above product and 1.42 g of dimethylformamide were mixed with ice cooling, and then 2.8 g of P₂O_ThreeCl_FourWas added. The mixture was heated at 100 ° C. for 2 hours, returned to room temperature, added with 2.5 g of sodium hydroxide dissolved in 50 mL of ice water, heated to 40 ° C. and hydrolyzed by stirring at room temperature. When the organic material was dispersed, extracted with ether, dried, filtered, concentrated, and chromatographed using a 750 mL hexane-dichloromethane gradient followed by 10% ethyl acetate (EtOAc) in dichloromethane. 2.0 g starting material, 1.3 g yellow oily product and 0.2 g dialdehyde were obtained. The product yield is 31% or 63% based on the starting material consumed.
Preparation of 1- (3-naphth-1-ylthio) propylthio) -4-vinylnaphthalene. 1.3 g of the above product was prepared from Wittig reagent (1.4 g of methyltriphenylphosphonium bromide and 3.3 mmol (1 eq) of BuLi dissolved in 30 mL of THF from 0 ° C. to room temperature over 1 hour and again To 0 ° C.). After stirring overnight at room temperature, 1.6 mL of methanol was added and the solution was concentrated and extracted with ligroin as in MTVN. The extract was partially concentrated to about 10 mL, diluted to homogeneity with dichloromethane, chromatographed on 20 g of silica gel and eluted with a 1: 1 solution of hexane: dichloromethane. 1.1 g (84%) of a viscous yellow oil was obtained, which was confirmed to be pure by NMR. Immediately after 30 minutes of vacuum drying, the material was mixed into the media preparation mixture. Embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.
[Brief description of the drawings]
FIG. 1 shows a basic holographic storage system.
FIG. 2 is a diagram showing the effect of several different photoactive monomers on the refractive index contrast of a recording medium.

Claims (41)

An optical product comprising a three-dimensional cross-linked polymer matrix and one or more photoactive monomers disposed on a substrate ,
The three-dimensional crosslinked polymer matrix and one or more photoactive monomers disposed on the substrate form a layer that is thick enough to exhibit useful properties;
The polymer matrix is formed in the presence of one or more of the photoactive monomers by a polymerization reaction independent of the polymerization reaction of the one or more photoactive monomers that occurs during subsequent recording;
At least one photoactive monomer includes a portion that is substantially absent from the polymer matrix, excluding the monomer functionality,
An optical product in which the matrix polymer and the polymer resulting from the polymerization of one or more photoactive monomers are compatible.   The optical article of claim 1, wherein the polymer matrix is formed by mercaptan-epoxy step polymerization. The optical product of claim 2 , wherein the polymer matrix comprises a polyether backbone. The optical product of claim 3 , wherein the one or more photoactive monomers are vinyl aromatic compounds. The one or more photoactive monomers are selected from styrene, bromostyrene, divinylbenzene, 4-methylthio-1-vinylnaphthalene and 1- (3- (naphth-1-ylthio) propylthio) -4-vinylnaphthalene. The optical product according to claim 4 .   The optical product according to claim 1, further comprising a photopolymerization initiator. The matrix is cationic epoxy polymerization, cationic vinyl ether polymerization, cationic alkenyl ether polymerization, cationic allene ether polymerization, cationic ketene acetal polymerization, epoxy-amine step polymerization, epoxy-mercaptan step polymerization, unsaturated ester-amine step polymerization, unsaturated ester. - mercaptan step polymerization, vinyl - silicon hydride step polymerization, isocyanate - hydroxyl step polymerization and isocyanate - are formed in the polymerization reaction selected from amine step polymerization, optical product of claim 1.   One or more of the photoactive monomers is acrylate, methacrylate, acrylamide, methacrylamide, styrene, substituted styrene, vinyl naphthalene, substituted vinyl naphthalene, vinyl ether mixed with maleate, thiol mixed with olefin, vinyl ether, alkenyl ether The optical product of claim 1, selected from:, allene ethers, ketene acetals and epoxies. The optical product of claim 8 , wherein at least one of the photoactive monomers comprises two or more refractive index contrast portions.   The optical product according to claim 1, wherein the product is a holographic recording medium. The holographic recording medium according to claim 10 , wherein the optical recording material comprising the matrix and one or more photoactive monomers has a thickness exceeding 200 μm. The holographic recording medium according to claim 11 , wherein the thickness exceeds 500 μm.   The optical product according to claim 1, wherein the product is an optical waveguide. The holographic recording medium according to claim 11 , wherein the medium exhibits Δn of 3 × 10 −3 or more. 15. The holographic recording medium of claim 14 , wherein the medium undergoes a thickness change of less than 0.3% upon polymerization of one or more of the photoactive monomers.   The optical article of claim 1, wherein 1 to 20% of one or more of the photoactive monomers is grafted to the polymer matrix. A process of manufacturing an optical product made of three-dimensionally crosslinked polymer matrix and one or more photoactive mono- mer,
Mixing the matrix precursor and the photoactive monomer,
Curing the matrix precursor to form a polymer matrix;
Consists of applying this to a substrate and forming a layer thick enough to exhibit useful properties ,
The matrix precursor is polymerized in a reaction independent of the polymerization reaction of the photoactive monomer during subsequent recording ;
A process for producing an optical product wherein the polymer resulting from the polymerization of the matrix polymer and the photoactive monomer is compatible. The process of claim 17 , wherein the polymer matrix is formed by a mercaptan-epoxy stage polymerization. The process of claim 18 , wherein the polymer matrix comprises a polyether backbone. The process of claim 19 , wherein the photoactive monomer is selected from vinyl aromatic compounds. The photoactive monomer is at least one of styrene, bromostyrene, divinylbenzene, 4-methylthio-1-vinylnaphthalene and 1- (3- (naphth-1-ylthio) propylthio) -4-vinylnaphthalene. The process according to claim 20 . The process according to claim 17 , wherein a photopolymerization initiator is mixed in the matrix precursor and the photoactive monomer. Depositing the matrix precursor / photoactive monomer mixture between two plates before curing;
Observing the parallelism of the plate and matrix precursor / photoactive monomer mixture during curing;
18. The process of claim 17 , further comprising adjusting the plate relationship during the curing process to improve the optical properties of the product, if necessary. The process of claim 17 , wherein the photoactive monomer comprises two or more refractive index contrast moieties. A process for producing an optical product comprising one or more polymers formed from a three-dimensional crosslinked polymer matrix and one or more photoactive monomers,
Placing a three-dimensional cross-linked polymer matrix and one or more photoactive monomers on a substrate to form a layer that is thick enough to exhibit useful properties;
Irradiating selected areas of a product comprising a three-dimensional crosslinked polymer matrix and one or more photoactive monomers;
At least one photoactive monomer includes a moiety that is substantially absent from the polymer matrix, excluding monomer functional groups;
The irradiation induces polymerization of one or more of the photoactive monomers by a reaction independent of the reaction in which the matrix polymerizes;
Providing a pattern to an optical article, wherein the polymer resulting from the polymerization of the polymer matrix and one or more of the photoactive monomers is compatible. 26. The process of claim 25 , wherein the polymer matrix is formed by a mercaptan-epoxy stage polymerization. 27. The process of claim 26 , wherein the polymer matrix consists of a polyether backbone. 28. The process of claim 27 , wherein the one or more photoactive monomers are selected from vinyl aromatic compounds. The one or more photoactive monomers are selected from styrene, bromostyrene, divinylbenzene, 4-methylthio-1-vinylnaphthalene and 1- (3- (naphth-1-ylthio) propylthio) -4-vinylnaphthalene. The process according to claim 28 . 26. The process of claim 25 , wherein the optical product is a holographic recording medium. 31. The process of claim 30 , wherein the optical recording material comprising the matrix and the photoactive monomer has a thickness greater than 200 [mu] m. 32. The process of claim 31 , wherein the thickness is greater than 500 [mu] m. The process of claim 30 , wherein the medium exhibits a Δn of 3 × 10 −3 or greater. 34. The process of claim 33 , wherein the medium undergoes a thickness change of less than 0.3% upon polymerization of one or more of the photoactive monomers. The photoactive monomer is acrylate, methacrylate, acrylamide, methacrylamide, styrene, substituted styrene, vinyl naphthalene, substituted vinyl naphthalene, vinyl ether mixed with maleate, thiol mixed with olefin, vinyl ether, alkenyl ether, allene ether, ketene 26. The process of claim 25 , comprising at least one group selected from acetal and epoxy. 36. The process of claim 35 , wherein the photoactive monomer consists of two or more refractive index contrast moieties. 26. The process of claim 25 , wherein the optical product is an optical waveguide. A formed Ru optical products from one or more polymers formed from three-dimensionally crosslinked polymer matrix and one or more photoactive monomer disposed on the substrate,
The three-dimensional cross-linked polymer matrix of the optical product and one or more photoactive monomers form a layer that is thick enough to exhibit useful properties;
The polymer matrix is formed in the presence of one or more of the photoactive monomers by a polymerization reaction independent of the polymerization reaction of the one or more photoactive monomers that occurs during subsequent recording;
At least one of the photoactive monomers consists of portions that are substantially absent from the polymer matrix, excluding monomer functional groups;
An optical product in which one or more of the polymers formed from the polymer matrix and one or more of the photoactive monomers are compatible. 39. The optical article of claim 38 , wherein the polymer matrix is formed by a polymerization reaction that is independent of a reaction in which the one or more photoactive monomers polymerize in the presence of the one or more photoactive monomers. . The matrix is cationic epoxy polymerization, cationic vinyl ether polymerization, cationic alkenyl ether polymerization, cationic allene ether polymerization, cationic ketene acetal polymerization, epoxy-amine step polymerization, epoxy-mercaptan step polymerization, unsaturated ester-amine step polymerization, unsaturated ester. 39. Optical article according to claim 38 , formed by a polymerization reaction selected from mercaptan stage polymerization, vinyl-silicon hydride stage polymerization, isocyanate-hydroxyl stage polymerization and isocyanate-amine stage polymerization. One or more of the photoactive monomers is acrylate, methacrylate, acrylamide, methacrylamide, styrene, substituted styrene, vinyl naphthalene, substituted vinyl naphthalene, vinyl ether mixed with maleate, thiol mixed with olefin, vinyl ether, alkenyl ether 40. The optical article of claim 38 , selected from:, allene ethers, ketene acetals and epoxies.

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